Least Influential Testers and Quality People with very High Influence - Which one is better ?

Yes, Testers with very high influence and with least influence can be bad for a particular project. Situation becomes worst when Developer working with such testers are not bothered about arguing on things and don't have strong opinions.

Why this came to mind and how I am concluding this?

Today I was sitting in my office and overheard a conversation between a tester in my team & relevant Developer. Tester had logged a bug which seemed to be as-designed. Developer gave one reason that it's discussed in a meeting and should be as-designed. On this Tester got annoyed and said - "I was not in that meeting, I guess. And with workflow makes perfect sense" ... and gave some reasons in favor of that. Developer was just listening and agreed to what that Tester told him. Developer didn't give  second thought on the reasoning given by tester and conversation happened in the meeting.

This is a typical example of Highly influential tester working with a Developer with less influence, weak onions etc. This way Developer end up doing/fixing things, what is suggested by Tester. Usually Testers have very strong opinions and they kind of convince other folks easily. For such Testers, Developers should be more attentive and in case of doubt, Developers should get opinion from Managements and product Managers who are responsible for product requirements.

Conversations become more interesting when more influential developers work with highly influential Testers  :-)

I have enjoyed such conversations during my career many times ! But believe me, it gives better results if both tester and developer discuss it constructively without thinking in terms of effort, time etc. Also it gives a wonderful experience for both the folks and help in improving their negotiation skills.

Now let's come to other thing when Tester is not very influential. Not being very influential doesn't mean anything bad, but Tester with least influence should not accept comments from developer or any other team members, if not convinces. And should try to follow the standard processes to share the opinion through Bugs, Email-discussions and let management take right decision rather accepting some comments conveyed through informal conversations.

Many times, Senior Developers give some technical reasons which may not be right from user's perspective. And if Tester is not convinced with those reasons, there is no point accepting things only because you can't influence others opinion.

Hope I conveyed my thoughts in right way. Please feel free to share your opinion about this through comments !!! That will be most appreciated.